Showing papers on "Microstrip published in 1997"

Design of millimeter wave microstrip reflectarrays

Abstract: This paper discusses the theoretical modeling and practical design of millimeter wave reflectarrays using microstrip patch elements of variable size. A full-wave treatment of plane wave reflection from a uniform infinite array of microstrip patches is described and used to generate the required patch-design data and to calculate the radiation patterns of the reflectarray. The critical parameters of millimeter wave reflectarray design, such as aperture efficiency, phase errors, losses, and bandwidth are also discussed. Several reflectarray feeding techniques are described, and measurements from four reflectarray design examples at 28 and 77 GHz are presented.

Theoretical and experimental investigations on rectangular dielectric resonator antennas

Abstract: Theoretical and experimental investigations on rectangular dielectric resonator antennas having a value of /spl epsiv//sub r/, in the range of 10 to 100 are reported. The resonant frequencies and radiation Q-factors of the lowest order "magnetic-dipole" modes are derived on the basis of a first-order theory. The accuracy of the model in predicting the resonant frequency and radiation Q-factor is verified by comparison with results of a rigorous theory and experiments. Various feeds for the antennas such as probe, microstrip slot, and microstrip line are described. Measured radiation patterns are shown and the effect of feed and mode degeneracy on the cross-polarisation levels is discussed.

The modeling, characterization, and design of monolithic inductors for silicon RF IC's

Abstract: The results of a comprehensive investigation into the characteristics and optimization of inductors fabricated with the top-level metal of a submicron silicon VLSI process are presented. A computer program which extracts a physics-based model of microstrip components that is suitable for circuit (SPICE) simulation has been used to evaluate the effect of variations in metallization, layout geometry, and substrate parameters upon monolithic inductor performance. Three-dimensional (3-D) numerical simulations and experimental measurements of inductors were also used to benchmark the model accuracy. It is shown in this work that low inductor Q is primarily due to the restrictions imposed by the thin interconnect metallization available in most very large scale integration (VLSI) technologies, and that computer optimization of the inductor layout can be used to achieve a 50% improvement in component Q-factor over unoptimized designs.

Demonstration of 110 GHz electro-optic polymer modulators

Abstract: Electro-optic modulation up to 113 GHz has been demonstrated using traveling wave polymer modulators. The modulation signal was directly detected at 1.3 μm using a laser heterodyne system with an external-cavity tunable semiconductor laser. The device optical response variation, as a function of frequency over the whole W band, was within 3 dB. A well-matched coplanar probe was used to launch W band millimeter wave driving power into the microstrip line electrode on the device. Based upon these measurements, high speed electrodes with integrated millimeter wave transitions had been fabricated and tested.

Dual-frequency patch antennas

Abstract: Dual-frequency patch antennas may provide an alternative to large-bandwidth planar antennas, in applications in which large bandwidth is really needed for operating at two separate transmit-receive bands. When the two operating frequencies are far apart, a dual-frequency patch structure can be conceived to avoid the use of separate antennas. In this paper, a critical overview of possible solutions for dual-frequency patch antennas is presented, and future perspectives are outlined. Geometries are discussed in particular.

Advances in microstrip and printed antennas

Abstract: Probe-Fed Microstrip Antennas (K. Lee, et al.). Aperture-Coupled Multilayer Microstrip Antennas (K. Luk, et al.). Microstrip Arrays: Analysis, Design, and Applications (J. Huang & D. Pozar). Dual and Circularly Polarized Microstrip Antennas (P. Hall & J. Dahele). Computer-Aided Design of Rectangular Microstrip Antennas (D. Jackson, et al.). Multifunction Printed Antennas (J. James & G. Andrasic). Superconducting Microstrip Antennas (J. Williams, et al.). Active Microstrip Antennas (J. Navarro & K. Chang). Tapered Slot Antenna (R. Lee & R. Simons). Efficient Modeling of Microstrip Antennas Using the Finite-Difference Time-Domain Method (S. Chebolu, et al.). Analysis of Dielectric Resonator Antennas (K. Luk, et al.). References. Index.

Experimental and simulation studies of the coaxially fed U-slot rectangular patch antenna

Abstract: Experimental and simulation results are presented on the coaxially fed rectangular patch antenna with a U-shaped slot. Experimental results include impedance bandwidth, copolar- and crosspolar-pattern characteristics and gain measurements. Simulation results are obtained mainly through the development of a FDTD code. It is found that the U-slot patch on a foam substrate of about 0.08/spl lambda/ thick can be designed to attain 20-30% impedance as well as gain bandwidths without the need of parasitic patches on another layer or on the same layer. The far-field patterns have good copolar and crosspolar characteristics. By altering the patch width or feed position, the wideband characteristic can be changed into a dual-frequency characteristic. Simulation results are in good agreement with measurements.

Theory and experiment of novel microstrip slow-wave open-loop resonator filters

Abstract: This paper presents the theory and experiment of a new class of microstrip slow-wave open-loop resonator filters. A comprehensive treatment of capacitively loaded transmission line resonator is described, which leads to the invention of microstrip slow-wave open-loop resonator. The utilization of microstrip slow-wave open-loop resonators allows various filter configurations including those of elliptic or quasi-elliptic function response to be realized. The filters are not only compact size due to the slow-wave effect, but also have a wider upper stopband resulting from the dispersion effect. These attractive features make the microstrip slow-wave open-loop resonator filters promising for mobile communications, superconducting and other applications. Two filter designs of this type are described in detail. The experimental results are demonstrated and discussed.

Implantable medical device microstrip telemetry antenna

Abstract: A microstrip RF telemetry antenna is formed on or within the exterior surface of an implantable medical device housing that is formed either of a conductive metal or of a non-conductive dielectric material The microstrip antenna is formed of an electrically conductive radiator patch layer that is laminated upon an exterior facing side of a dielectric substrate layer of relatively constant thickness A conductive ground plane layer is formed on the opposite side of the dielectric substrate layer to extend parallel to and at least coextensively with the radiator patch layer The radiator patch layer is coupled to the transceiver circuitry within the implantable medical device housing by a feedthrough extending through the dielectric substrate layer, the ground plane layer and the implantable medical device housing side wall If the implantable medical device housing is conductive it may form the ground plane layer over which the dielectric substrate layer and the radiator patch layer are formed through deposition or other techniques If the implantable medical device housing is formed of a suitable non-conductive dielectric material, the ground plane layer is formed on an interior surface thereof and the radiator patch layer is formed on an exterior housing surface thereof, preferably by deposition techniques The ground plane layer may be recessed to form a cavity backed ground plane that receives the dielectric layer and radiator patch layer within the cavity The exterior surfaces of the radiator patch layer, the dielectric layer and any exposed surface of the ground plane layer may be electrically insulated by a radome layer

Microstrip antennas on synthesized low dielectric-constant substrates

Abstract: Micromachining techniques using closely spaced holes have been used underneath a microstrip antenna on a high dielectric-constant substrate (/spl epsiv//sub r/=10.8) to synthesize a localized low dielectric-constant environment (/spl epsiv//sub r/=2.3). The measured radiation efficiency of a microstrip antenna on a micromachined 635-/spl mu/m thick /spl epsiv//sub r/=10.8 Duroid 6010 substrate increased from 48/spl plusmn/3% to 73/spl plusmn/3% at 12.8-13.0 GHz (including 3.3-cm feed line losses). We believe that this technique can be applied to millimeter-wave antennas (microstrip, dipoles, slots, etc.) on silicon and GaAs substrates to result in relatively wideband (3-6%) monolithic microwave integrated circuits (MMIC) active antenna modules for phased-arrays and collision-avoidance systems.

Theory of intermodulation in a superconducting microstrip resonator

Abstract: The penetration depth and surface resistance of a superconductor depend upon the superfluid current density. This dependence gives rise to nonlinear mixing in a superconducting microstrip resonator. Here we discuss the problem of intermodulation in which two signals at ω1 and ω2, laying within the pass band of a microstrip cavity resonance, mix and generate a signal at 2ω1−ω2. An expression relating the power generated at 2ω1−ω2 to the power transmitted at ω1 and ω2 is given. We focus on the high-Tc superconductors where it is believed that the order parameter has dx2−y2 symmetry. We find for a resonator with a large unloaded Q that intermodulation arises dominantly from the reactive nonlinear inductance of the superconducting film.

Photonic band-gap materials for high-gain printed circuit antennas

Abstract: It is found through a vector integral-equation analysis and the reciprocity theorem that the gain of a microstrip antenna can be greatly enhanced with a photonic band-gap material layer either as the substrate or the superstrate. The beam angle is found to coincide with that of a leaky-wave mode of a planar-grating structure. This observation suggests that high gain is due to the excitation of strong leaky-wave fields.

Dual-frequency triangular microstrip antenna with a shorting pin

Abstract: This paper presents a novel design of triangular microstrip antenna with dual-frequency operation. In this design the microstrip patch is short-circuited using a shorting pin and fed by a single probe feed. By varying the shorting pin position in the microstrip patch, such a design can provide a large tunable frequency ratio of about 2.5-4.9 for the two operating frequencies. Experimental results for operating at frequencies of 464 and 2276 MHz are presented and discussed.

A broadband uniplanar microstrip-to-CPS transition

Abstract: We report our recent investigation of a novel uniplanar transition between microstrip lines and coplanar strips (CPS) which is to be utilized in our velocity-matched distributed photodetector (VMDP). Both FDTD simulations and X-band experiments show broadband, low return loss performance of this newly proposed structure, with a measured 3 dB insertion loss bandwidth of 68 percent for the case of a balanced back-to-back microstrip-to-CPS transition.

Simulation and experiment of photonic band-gap structures for microstrip circuits

Abstract: We report the first comprehensive investigation of synthesized dielectric materials which possess distinctive stopbands for microstrip lines. Four types of these photonic band-gap (PBG) structures have been simulated using FDTD. Experiment with a honeycomb-lattice PBG line shows excellent agreement between theoretical prediction and measurement.

Microstrip ring resonator for soil moisture measurements

Abstract: Development of a successful remote sensing instrument for soil moisture relies on the accurate knowledge of the soil dielectric constant (/spl epsiv//sub soil/) to its moisture content. Two existing methods for measurement of dielectric constant of soil at low and high frequencies are, respectively, the time domain reflectometry and the reflection coefficient measurement using an open-ended coaxial probe. The major shortcoming of these methods is the lack of accurate determination of the imaginary part of E/sub soil/. In this paper, a microstrip ring resonator is proposed for the accurate measurement of soil dielectric constant. In this technique the microstrip ring resonator is placed in contact with soil medium and the real and imaginary parts of E/sub soil/ are determined from the changes in the resonant frequency and the quality factor of the resonator, respectively. The solution of the electromagnetic problem is obtained using a hybrid approach based on the method of moments solution of the quasistatic formulation in conjunction with experimental data obtained from reference dielectric samples. Also, a simple inversion algorithm for E/sub soil/=E/sup '//sub r/-j/spl epsiv/E/sup "//sub r/ based on regression analysis is obtained. It is shown that the wide dynamic range of the measured quantities provides excellent accuracy in the dielectric constant measurement. A prototype microstrip ring resonator at L-band is designed and measurements of soil with different moisture contents are presented and compared with other approaches.

Low-dispersion thin-film microstrip lines with cyclotene (benzocyclobutene) as dielectric medium

Abstract: We report on thin-film microstrip lines (TFMSLs) fabricated on low-resistivity Si with polymerized cyclotene as the dielectric between signal and ground conductor, all on top of the wafer Electro-optic high-frequency characterization of the TFMSLs reveals negligible modal dispersion up to the highest frequencies of 10 THz In spite of the high substrate conductivity, the attenuation is low (⩽1 dB/mm at 100 GHz) Over the full frequency range, it is dominated by conductor losses and not by absorption in the dielectric With these dispersion and attenuation properties, TFMSLs are an attractive alternative to coplanar waveguides, with the additional advantage of immunity against substrate absorption and radiation losses

Feasibility study of optically transparent microstrip patch antenna

Abstract: The paper presents a feasibility study on optically transparent patch antennas with microstrip line and probe feeds. The two antennas operate at 2.3 GHz and 19.5 GHz respectively. They are constructed from a thin sheet of clear polyester with an AgHT-8 optically transparent conductive coating. The experimental results show good radiation patterns and input impedance match. The antennas have potential applications in mobile wireless communications.

Small dual-frequency microstrip antenna with cross slot

Abstract: A new design of single-feed, reduced-size dual-frequency rectangular microstrip antenna with a cross slot of equal length is presented. The frequency ratio of the two operating frequencies is mainly determined by the aspect ratio of the rectangular patch, and the reduction in the two operating frequencies is achieved by cutting a cross slot in the microstrip patch. Details of the experimental results for such a design are presented and discussed.

Microwave Transmission Line Impedence Data

Abstract: A compendium of data for computing the characteristic impedance of transmission lines based on physical dimensions. Covers both conventional structures and unusual geometries, including coaxial, eccentric and elliptic coaxial, twin-wire, wire-above-ground, microstrip and derivatives, stripline, slabline and trough line. Also details numerous configurations of coupled lines.

Simple design of dual-beam leaky-wave antennas in microstrips

Abstract: The paper describes the design of microstrip leaky-wave antennas for single and dual-beam applications. Dispersion curves for the first higher order mode are given by analytical expressions with the help of a simple cavity model. From knowledge of the propagation characteristics, the radiation patterns of the leaky-wave antennas are easily computed. The antennas are excited by open-ended CPW lines which both present a good coupling efficiency and high potentiality for the insertion of active circuits. Several C-band applications on various substrates are presented, showing the usefulness and the easy design of microstrip leaky-wave antennas for the realisation of steerable dual-beam patterns.

Compact triangular microstrip antenna

Abstract: Loading a triangular microstrip antenna with a shorting pin can significantly reduce the antenna size at a given operating frequency. Experimental results of such a triangular microstrip antenna are presented. Variations of the resonant frequency of the triangular microstrip patch with different shorting-pin positions are given, and comparisons of the compact and conventional triangular microstrip antennas are also presented and discussed.

Microstrip reflectarray with elements having variable rotation angles

Abstract: Two Ka-band, half-meter diameter, circularly polarized microstrip reflectarrays have been developed. One has identical square patches with variable-length phase delay lines. The other uses identical square patches and delay lines with variable element rotation angles. Although both antennas demonstrated excellent efficiencies, adequate bandwidths, and low average sidelobe and cross-pol levels, the one with variable rotation angles achieved superior overall performance. It is believed that these are electrically the largest microstrip reflectarrays (6924 elements with 42 dB gain) ever developed. It is also the first time that circular polarization has been actually demonstrated using microstrip patch elements. It is known that, if a circularly polarized antenna element is rotated from its original position by /spl psi/ degrees, the phase of the element will be either advanced or delayed by the same /spl psi/ degrees. Hence, the technique of rotating circularly polarized elements to achieve the required phases for a conventional array to scan its beam has been previously demonstrated. This technique was also demonstrated for a spiraphase reflectarray where physically large spiral elements with discrete and limited switchable phase states were used to scan the beam. Here small and low-profile printed microstrip elements are used in a reflectarray with continuous variable angular rotations to achieve far-field phase coherence. It has been previously proposed that a controllable miniature or micro-machined motor can be placed under each patch element of a reflectarray to scan the beam to wide angular directions. By doing so, the high-cost/high-loss phase shifters, T/R modules, and beamformer are no longer needed in a beam scanning antenna.

Modeling planar arbitrarily shaped microstrip elements in multilayered media

Abstract: Microstrip elements of arbitrary shape are modeled in multilayered media. The Green's function for the multilayered structure is developed in a form useful for efficient computation for interacting microstrip elements, which may be located at any substrate layer and separated by an arbitrarily large distance. This result is of significant value to a variety of applications in wave propagation besides those discussed in this paper. The mixed-potential integral-equation (MPIE) method is developed in the spatial domain. Examples for regularly/arbitrarily shaped geometries in single and multilayered media are presented. These involve the optimization of an open-end microstrip, a radial-stub microstrip, a five-section overlay-gap-coupled filter, and a circular-patch proximity-coupled microstrip antenna. Very good agreement with measurement and other published data is observed.

Microwave circuit package

Abstract: A microwave circuit package (10) includes a metallic base plate (3) on which are mounted a plurality of monolithic microwave integrated circuits (MMICs) (11,12,13) and a spacer (15), made of a dielectric material, separating the MMICs (11,12,13) from each other, and the MMICs (11,12,13) and spacer (15) are sealed in the package (10). The provision of the spacer (15) substantially reduces the volume of the interior space of the package (10). A dielectric substrate (14) having generally the same height as substrates of the MMICs (11,12) may also be mounted on the metallic base plate (3), and a strip conductor (14d) may be provided on the dielectric substrate (14) so as to form a microstrip line thereon.

A millimeter waveguide and a circuit apparatus using the same

Abstract: A millimeter waveguide is disclosed which includes: a first single crystal substrate having a groove therein; a conductor film on a surface of said groove and a surface of said first single crystal substrate connected to said surface of said groove; a second single crystal substrate covering said conductor film; and a microstrip line on a surface of said second single crystal substrate, exposed to a cavity in said groove. A protruding portion may be formed on a bottom surface of the groove. The microstrip line including foundation (nickel chromium) and conductive (gold) layers may be formed on a surface of the groove. A protruding portion may be formed on the second single crystal substrate, wherein the height of this protruding portion is less than the depth of the groove. A millimeter waveguide for a resonator is also disclosed wherein a cavity is formed in substrates with grounding conductive layers on surfaces of the cavity, a probe extending from a microstrip line on a top surface of the substrates. Similar millimeter waveguide is also disclosed wherein the probe is replaced by magnetic field coupling structure. A circuit apparatus is also disclosed which comprises the millimeter waveguide apparatus mentioned above mentioned and an active circuit fixed on the millimeter waveguide apparatus.

Slot-coupled DR antenna for dual-frequency operation

Abstract: To achieve dual-band operation or wider bandwidth, a new configuration of dielectric resonator antenna is proposed. This structure consists of two rectangular dielectric resonators displaced near two edges of a single slot in the ground plane of a microstrip line. The measured impedance and radiation patterns for two cases are presented. The results for typical examples indicate that an impedance bandwidth twice that of a single element or dual-frequency operation at two separate bands can be achieved.

Waveguide-to-microstrip transition for mmwave and MMIC applications

Abstract: A waveguide-to-microstrip transition package (30) for processing electromagnetic wave signals includes a waveguide (32) for directing the signals to the input of the waveguide (32). A substrate (34) overlaps the input of the waveguide (32) to form a hermetic seal. A metallized probe (36) conducts the signals to a microstrip line (40) and is patterned upon the substrate (34). The transition (30) also includes an iris (48) formed from a metallized pattern on the opposite side of the substrate (34) from the probe (36). The special design of the probe (36), the structure of the iris (48) and the wave guide cavity (46) above the probe (36) allow impedance matching and efficient signal transfer from waveguide (32) to microstrip line (40) or from microstrip line (40) to waveguide (32).

LIGA micromachined planar transmission lines and filters

Abstract: This paper introduces a new class of three-dimensional (3-D) micromachined microwave and millimeter-wave planar transmission lines and filters. The LIGA process allows tall (10 /spl mu/m-1 mm), high-aspect ratio metal structures to be very accurately patterned and is compatible with integrated circuit-fabrication processes. The tall metal transmission lines will enable the development of high-power monolithic circuits as well as couplers and filters that require very high coupling. Using conductor thickness as a new variable in filter design permits the fabrication of elements requiring a wider than usual range of even- and odd-mode characteristic impedances by lowering the attainable odd-mode impedance without greatly influencing even-mode impedance. Bandpass and low-pass filters fabricated using 200-/spl mu/m tall nickel microstrip lines are demonstrated at X-band. Insertion losses of the network testing setup and waveguides were calibrated out using the thru-reflection-line (TRL) calibration method via LIGA-fabricated calibration standards. The high aspect ratio and slope that the LIGA process offers will enable the design of end-coupled narrow-band bandpass filters and planar side-coupled 3-dB couplers. Filter structures were fabricated possessing coupling gaps with aspect ratios of better than 6.75 and conductor sidewall slope >89.9/spl deg/, figures that are easily obtainable with the LIGA process. Additionally, W-band 3-dB coplanar waveguide-coupler LIGA geometries suitable for implementation on gallium arsenide or membrane (i.e., air dielectric) substrates are presented. A thin film-to-LIGA tapered waveguide transition is presented which will allow integration of conventional planar transmission lines with these LIGA devices.

Transmission-line analysis of a capacitively coupled microstrip-ring resonator

Abstract: The resonant frequencies of a microstrip-ring resonator capacitively coupled to a feed line are accurately analyzed using a transmission-line model. By making use of ABCD- and Y-admittance matrices, a compact closed-form expression for the input impedance of the ring alone is analytically derived and shows that the ring ran be equivalently viewed as a frequency-dependent capacitor. The coupling gap is then modeled by an equivalent L-network comprising a parallel and a series gap capacitance obtained by modifying Garg and Bahl's closed-form expressions for an end-to-end microstrip gap. By simplifying the parallel and series combinations of the overall equivalent circuit, the total input impedance looking from the feed line to the gap is analytically derived to predict the resonant frequencies. To verify the analysis, the resonant frequencies of the capacitively coupled ring resonator have been accurately measured, with the experimental results showing very good agreement with the theoretical predictions.